The aim of the invention is to provide a bicycle disc rotor using two types of members different in material for hardly causing inconveniences when fixed to a hub or a mounting member. The bicycle disc rotor 22 is a rotor for a bicycle disc brake device to be mounted on the wheel hub of a bicycle. It comprises the mounting member 22a, a rotor member 22b, and a caulked pin 22c. The mounting memberis mountable on the hub. The rotor member has a ring shaped first member 90, ring shaped second members 91 arranged in close contact with both sides of the first member and formed of a material having wear resistance higher than that of the first member, fixing holes 90d, 91d formed through the first and second members, and a recessed portion 91e formed ranging from one face of the second member to the periphery of the fixing hole 91d. The caulked pin is mounted through the fixing hole of the rotor member for fixing the rotor member to the mounting member.